1. Field of the Invention
The present invention relates to an oxygen generating materials, carbon dioxide absorbing materials, and transport system and transport method of live fishery products for preventing vitality deterioration and death of live fishery products.
2. Description of the Related Art
Methods of transporting live fishery products while keeping the likes of edible natural fish, cultivated fish, shellfish or aquarium fish alive can be divided broadly into transport without using water (which will be referred to as "waterless transport"), transport using tank (which will be referred to as "tank transport"), and transport using plastic film bag (which will be referred to as "plastic transport").
Waterless transport is a method wherein fish are transported without using water while being exposed to air, and is used for carp, crucian carp, loaches, prawns and the like. Since it is easy for the fish to fall into a condition of hypoxia, waterless transport can only be used for transports of short periods of time.
Tank transport is a transport method wherein oxygen is supplied from the oxygen cylinder to the water tank installed on a truck while letting the fish swim therein, and is used for transports in large amounts and relatively long distances. However, as this method requires costly specialized equipment, there is a problem in that the usage thereof is limited since transportation expenses become costly.
Furthermore, Japanese Patent Laid-Open Publication No. Hei 4(1992)-26808 proposes a transport method wherein fish, water and oxygen are placed in a receptacle equipped with an air pump and carbon dioxide absorbing tank on the outside while circulating air therein. However, as this method also requires costly specialized equipment, there is a problem in that the usage thereof is limited since transportation expenses become costly.
Plastic transport is a transport method wherein water and live fishery products are placed in a plastic film bag, sealed hermetically while leaving headspace, and further placed in a corrugated cardboard box or the like, and is used for small-scale and short-time transports. Plastic transport is an easy and low-costing method, and is widely used for transporting various kinds of cultivated fish, natural fish and aquarium fish. However, with the plastic transport method, water temperature during transportation, concentration of dissolved oxygen and water quality cannot be controlled, thereby leaving a problem in that, even within a 24-hour transport, vitality deterioration and death of fish during transport are likely to occur.
Therefore, with plastic transport, various ideas such as lowering the temperature of water that is hermetically sealed together with the fish, filling the headspace with gaseous oxygen, and ceasing the provision of feed have been employed in order to prevent vitality deterioration and death of fish during transport.
However, the employment of these methods is still usually insufficient in preventing vitality deterioration and death of live fishery products during the transport thereof. Particularly during the summer season when the temperature rises, vitality deterioration and death of fish occur, thereby leaving a problem in that the product value of such live fishery products being significantly reduced. With respect to edible fish, the price of dead fish is reduced to less than half of that of live fish. This is even a more serious problem concerning aquarium fish, whereby an aquarium fish that dies during transport becomes valueless. Furthermore, even if the fish loses vitality or a single fish inside the transport bag is to die, there is a problem in that the product value will be significantly reduced.
Particularly, transports to distant places requiring 24 hours or more is extremely difficult with conventional plastic transport technology as vitality deterioration and death of fish are likely to occur.
Moreover, as oxygen generating materials to be used for the transport or the like of live fishery products, a type wherein an aqueous solution of peroxide and a decomposition agent thereof are packaged with a multi-layered package (Patent Laid-Open Publication No. Hei 1(1989)-103902), a type wherein peroxide and the like are covered with a water-permeable sheet including a layer of active carbon (Patent Laid-Open Publication No. Hei 5(1993)-306104), and a type wherein a composition of hydrogen peroxide adduct and the like and a solidifying agent are packaged (Patent Laid-Open Publication Hei 7(1995)-289114) and so on have been proposed. However, a type which fulfills all such conditions as no elution of composition components into the water upon usage, easy operation, steady generation of oxygen for a long period of time, low manufacturing cost, and outstanding preservation stability has not been provided heretofore.